Assigstobs to gel-tebai



March 19, 1929. KRAPE ET AL 1,706,173

ELECTRIC BRAKING I Filed May 25, 1927 VoHa c BaIanc ing Relay Inventor-s: Rudolph D. Knape. WLIILam 5.H.HamLlton,

The'w Attorneu Patented him. 19, 1929.

warren stares mam RUDOLPH D, LEE-APE, OF SCHENECTAD'Y, AND WILLIAM S, H. HAMILTON, OF LABOR- MONT, NEW YORK, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION or NEW YORK.

ELECTRIC Application filed May 25,

The invention relates to electric brakmg,

particularly regenerative electric braking such as obtained on electric locomotives when the driving motors are excited to operate as motors. j

More specifically .the improved automatic control apparatusof the present invention is variable factors which are" encountered in the-regenerative braking operation of ele e trio locomotives such, for example, as variations in the line potential, variations dueto initiation of braking operation from rest and following motoring operation, yariationdue tosingle and multiple unit locomotive regenerative operation, variations in the speed .of

=the braking generators due to dilferencesgin diameteimof the driving wheels of mult ple unit locomotives, as well as variations in the braking effect dueto changes in the grade, all of which otherwise would require considerable attention and corresponding manipulation of the control apparatus .by.-the.

operating engineer. V Briefly, the improved control apparatus of thepresent invention '18 arranged automaticondition for regenerative braking operation either starting from rest or fOllOWll'lgiZhG motoring operation and with both single or.

multiple unit locomotive control, Furthermore all possibility of obtaining a danger ous or excessive regenerative voltage on the motors during the initiation of braking is effectively prevented. Moreover, the regenerative braking circuit is arranged to be established automatically only when the motor voltage is iii-proper relation with the existing line voltage to insure a smooth initi ation of the brakingoperation. After the initiation of regenerative braking operation,

the braking effect is automatically maintaincd substantiallyat a stable value that may .bepreselected by the engineer to meet the particular service conditions encountered ir-. respective of variations in line potential, grade, or-minor variation in the speed. of the ;-rcnerators. y

In carrying the invention into effect, the

; drawing.

BRAKINGQZ 7 1927. Serial No. 194 ,i206.

regenerative. braking operation is initiated under the..automat1c control of a voltage balancing relay responsive to both. the..line ,voltage and'; the; regenerative voltage of the motors. ,flhe; regenerative. volta e of the motors is;,al ltomatic ally regulated by constrolling 'the exciter ,thenefoi through the r en y 9i cou t r fl c d the control ofa regulator, gQf, .th vibratory typei which cooperates [fwithQ the voltage balancing relay so as to1prevent theregenerative voltage of the motorsQfrom becoming intended automatically to take care of many to maintain the excitation of thelmot'orslatia selected.;value,,1rrespective of. variations in speed of the exciter fonfthe motors ,thereby greatly fac litatin g multiple init operation of regenerative br'akin'g locornotives having. 7 separate; motor .,generat or Sets, for exciting the eters; The; vibratory regulator and r matically mainta n theregen erative braking 'currentgat a selected ,va'luei'ivhich maybe varied at will the operating ,engineerfim dependently} j the .ot p e iously noted,

- Thev s ngle. figure e1 le T em ac omp ny draivingis a simplified circui't diagram of an fi m o me w egen ra v br k g callv to brim the motors into the ro er I g).

iappara tu sl of. the presentdnvention. It \vill be understood thatlo'comotives operated in multiple ;unit are provided with control. s s tems duplicating thatv illustrated .in the As showniri the drawing the electric locomotive. has four driving motors. The four motor ar matures.A to A are adapted to operate in seriescircuit-as shown or in any other desired combination "as load driven generators to return current to the power supply line 10 through ithetrolley T when the line switch 11 is closed and the corresponding field windings F to F of the motors are excited from the .exciter, E. The exciter E-and thefieldwiridingF? F and F F 4 in parallelare in 'aj closed excitation circuit including the fixed resistor R and the adjustable resistor R Resistor R also is included-in the regenerative braking cir cuit extending from thelground connection throughfthe resistor. R the, arma u sof the motors A to in series circuit, the adjusthlble i esl st'o rs' 3 and. aielliiie switch 11 to the trolley T. Exciter E is driven by ewes-t le mew p e a ly y a e M :eee i 19 f TQ JhQ VBWY l ie. I- h exciterhe d winding 12 is separately excited from a suitable supply source indicated as battery B in the drawing.

The exciting current'of'the field winding 12 is regulated by varying the counter voltirge of the shunt wound motor C. E. M. F.

o eratin \Vindifig 1'7 and @dupeieon' psi-warme effecting vile short eiietfitifrg of field wind-ihg 13 of the c o'tin'tier E. M. 'F. motor in or'derto' regulate-the eXe'it-ttidn of the 'exc itc r' field min ling T2. The main winding 17 "of the ef-g ams is connected to be energized in 'accdidan't'eivitlli the voltage ticross the arinatttre or excite? "E with an ra nees-re s eming resistor R in circuit therewith. The r'e'gfl ator auxiliary winding 18 is energized in acfiordanee the current in the regenerative braking circuit throu 'g'h the agency of the shin ft 20'. The regulator auxiliary winding -19' funtiions as im 'nti-hu'nfihgg'windhi and is connected mos the fllliiifttire of he o. M. F. niotor. 'The icyulator winding 19' acts Cmmflafieiy with eta-s ed to-the'r'nai'fiwir'iding 17 while the, current re'sOnSiVie'WEnding T8 acts difierentifilry with e main Winding l7. l

In order to n'fai' ltthin a 's ullstantiafly 65nstant loitd :on the counter "E. M. F. in'otor an eddy current "brake 21 is rricharficdlly conne'ctcd to he driven by the motor and is provid c'd with the we retarding windings 22 and 23. inding 2 2 is eriergized directly from the battery B while the wix'tding 23 is connected in the a'rtnatiire circuit of the C. E. F. motor tobe energized 'in accord aiice with the exciting cmrcnt supplied to the cxcitcr field winding F As will be pointed out more fully hereinufter, the initiation of regenerative hrzthing o'liieratio'n is under the automatic control of the lta e e balancing relay 30 having the winding 31 connected through the protective resistor 32 to the trolley T to he encrgized in accordance with the voltage of the line 10. The winding '33 of the balancing. relay on the other hand is connected to be energized responsively to the regenerated volt-age of the motors indicated. The auxiliary windingB't of'the voltage balancing relay is connected aeins's thefieid winding s F F F F of the regenerative braking n ota irs in order .to compensate the action oi the voltage responsive winding 33 during certain phases of operation.

"other awn-o1 elements i'l'h'lstrateld will he uhderst'ood from the operation of the regenerative braking control system which is it's follows:

Suitable controllers, which have been omitted from the drawing for the sake of clarity, are operated by the enginem' to es- -.ta'h'l'ish the motor and exei'ter connections the circuit.

\Vhen the motor arniatures AA are driven by'the load,- the excitation of their respective field winding results in the motor til-matures gcnerz'it-ing a voltage. This voltage is impressed upon the winding 33 of the balancing "relay 30. kt the same time the voltage of the cxciter E is impressed upon the mean winding '17 of the automatic regulfttir 15. The regu'lator contact 16 conscqucntly vibrated to open and close the short circuit arountl the field winding 1? of the C. E. M. F. motor and thereby vary the counter voltilge of the motor so :1: in inaiiitain the Voltage of the cxcitcr l) at :1 value rlctein'iiued by the setting of the Hiljustab'le resistor R. The resistor R is a ljusted 'h the engineer to PXOtlllt't desired 'i'egencrative braking cfi'ect corresponding to the serviceconditions encountered. \Vith al of the resistor R in. circuit with the reguliitor tipcrating winding 17, the braking cliect is maintained at the maximum valuiwhile with all of the resistor R" removed from the circuitthe minimum braking effect vrill be obtained.

In 'order,- however, to prevent the generation of an excessive or dangerous motor voltage during the initiation of regenerative braking operation and before the line switch 11 is closed to complete the braking circuit, the voltage balancing relay 30 cooperates with the regulator in controlling the short circuit around the field winding 13 of the C. E. M. F. motor. For example, in case the resistor R is adjusted to produce a voltage on the exciter E such that the resulting excitation of the motor field windings F to F. causesthe regenerated voltage of the motors to exceed a predetermined value, the winding 33 of the voltage balancingrelay 3Q is sutiiciently energized to predominate over the'line voltage winding 31'.and 'op erate-' the relay 'contact 35 out of engagement'with its rightdiand cooperating contact and into engagement with its "left hand-contact. The disengagement of 'the ijightha'n'drelay contact insures that tl1e"'-short"circuit around the C. E. M. F.

'motor field winding 13 is removed'so that the counter voltage of the motor.becomes effective to reduce the exciting current sup- .plied to the excite'r field Winding 12.- The reduced excitation of the exciter in turn red uces' the excitation of the '-regenerative braking motors. 1 '.;Howev'er, engagement of the contact of thevoltage f responsive relay with its left hand centact completes an energizing'circuit 'fori'the'op ei'ating eleetro-magnet of the line s'witch "'11 through a circuit extending:

from the ibattery B through the control switch 9 4, conductor 45, contact 35 the 0p- "-erating"winding' 40 and thence to ground. -Thereupo'n the 'line switch 11 is closed to connect the'motorarmatures A, A to the supply line 10 for regenerative braking operation with the resistorR inthe braking circuit. fSince the'regenerative voltage of themotors is substantially equal to the line voltage there is no appreciable flow of either braking current or motoring currout through the resistor R and the relay contact 35 returns to its righthand position. To increase the excitation. of the motor field windings F F" to produce Braking operation, the successive sections of the resistor R are removed from the excitoncircuit thereby permitting full excitation of the niotor field windings in accordance with the voltage of" the excite-r E, As a result the regenerative voltage of the motor armatures A to A is increased and the excitation of the winding 33 of the voltage balancingrehry is correspondingly increased. T he resistor R serves to limit the flow 0t regenerative braking current under these conditions.

Due to the resulting predominance of the motor voltage: responsive winding 33 over the line voltage responsive winding 31. the relay contact 35againis drawn out of engagement with'its' right hand contact establishin a short circuit relay returns to its-initial positionthereby reestablishing the short circuit around-the shunt fieldwindingfof the C. E. Mi Fi motor.

In this; way the contact 35'of the voltage balancing relay 30 is operated alternately to open and close the'short izircuit around the C. E. M. F motor field wiriding so maintain the regenerated "voltagw of the motors substantiallyequal "tothe line voltage. Under these conditions 'the *regulator 15 remains inactive"? f 31- i \Vith the-motor and the line voltage 'substantially balanced, the current limiting-resistor R may be shunted 'from'the regener ative braking'circuit by the successive operation of the switches 47','48'and'49.-]Upon the closure of switch' 49 the normally open auxiliary contact 43 thereof is closed; thus around'the Tight hand contact of the voltage bala-ncingjrelay '30. This transfers the automatic control of regenerative brakingoperation -'from the voltage balancing relay 30 to the regulator- 15. The latter thereupon -operates its-contact 16 to periodically short-circuit the-G. M. F. motor field winding 13 -to-'-'maintain the voltage of the exciter E at the value determined by the adjustment ofthe Tesistor R. The adjustment of the resistor R, as previously pointed out, causes-the regulator 15 automatically to maintain the exciter voltage at the proper value to produce the desired regenerative braking effect under the existing conditions of grade and other variable factors. VVit-h the exeiter voltage at the selected value. the excitation of the motor field windings FF produces the necessary voltage in the motor armaturcs iJ-A required to return the regencrative braking current to the supply line 10.

In case the voltage of the supply line 10 should vary and inversely vary the current returned (hereto, the differential current rcpad - di-fi erent conditions-of operation. .temally reducesgtne' opportunity i':or' 1m- --the :varimtionin voltage drop inthe resist .21 .Rkinherently results in an increase or a decrease in the field excitation of thegmoters tending to conuespondingly avaty the .moto'r nol t-asge and thereby compensa-tefor the voltj-F'ron1-.- th e -fo1'egoi ng-- i.t---will be seen hat the improvementsoiour present invcn on render the initiation of regenerative braking operation and the control thereof entirely. automatic and independent of the many variable teeters encountered during This maage; variation in, the-line.

proper operation. due to lack of attention ,or ski-ll in the engineer-and at all tnnes insures ajsmooth transitionjmto braking operation eithexgsta'rtingfromrest or following motor- -mgoperation- 1 lrvhatwe claimas snow and desire toseeure by Letters Patent of the United States, f. i

.1. The-combination of a regenerative braking dynamo-electric machine having a .field minding; means for,.-separzitely exciting maid fieid wipdingto. efi'ect regenerative brakingoperation of said innchine, automaitic control means for thejsaid separate exciting means ineludinga ar-i-abic voltage counter-electromotive force dyrmmo-eimt ic machine; and an, automatic regulator tor regulating the excitation-cit said nnrchinc in accordance. with predetermined braking con ditions.-

cite-r w-rlta-ge and the r said machine for regulating the 'Q-XCliltiiOl'i of .sind (:XCIi/CL'.

2. he combination ofa regenerative oral;- i'ng dynamo-electric machine, an exciter tier exciting seidnznachine to .eilect regenerative braking operation thereof, means for separately exciting the exc-itcr, and means including a variable volt-age counter-electromotive force dynamwelcctric machine controlled jointly in accmdauice with the oxgenerated current of 3. The combination of a relive braking dynamo-electric machine having :1 field winding. an'exciter for excrtingsaizi field windin to efiect re encrative braking operationof saidmaehine, means for sep-i arately excitingseid exciter, a shunt-wound motor having-Its armature connected mthe thebra-lting circuit.

excitation circuit of said exciter, and an :ing .wind ing for said regulator energized in accord once-with predetermined conditions .in the braking circuit to vary the coiinterelcctroinotive force of the motor in accordance therewith, and means for varying the, cnergization saidregnlator .wiiidj ng independently. of the electrical .condi'tionsin 5. T he ccnnb-iuatiozr of a regenerative braking dyrnrmo-eiectrie machine having a iicid winding, an excitcr for exciting said Eel l winding to effect regenerative braking operation of said machine, means for $610- arately exciting saidexciter, a shunt-wound motor having its armature connected in the gcx itatiorgcircuit of sz ridi exciter, an: automatic regulatorhaving 2', 'vibmtoryflcoiiraet for controlling. a short circuit around the shunt fici'd winding. of said motor, isaid regulator having an operating lwinding connected 7 to be energized responsively to the volt ego of said exciter,and,a. different rel operating winding connected to, be energized" accerdancc with the regenex iftivev:eurrent of said ,dynamdelectric machine-..

6. ihe geoinbinationof. regenerative dyinuno-eiectric machine having afield winding, ancxciter fQrQCXCiQ-lflg said field windiiw to effect said. rcg'encrative'braking opution of said machine, means for scpurnteiy exciting said exciter. a shunt-wound 1 having its armature connected in the a-zncrtatioi circuit of said exciter, an automatic regulator having a yihratory contact or controliing a short circuit around the shunt field winding ofsnid motor, said regulator he: ing an operating winding connected .1;- ho one: Led rcsponsively to the voltage of said excite), and a dilfcrcntinloperating aa'indine connected to he energized in accordance with the regenerated current of mid dye:nae-electric machine. and means for varying the excitation of said first regulator operating winding independently of the voitagc of said cxciter to controlthe regenerative braking current of said machine.

7. In a re -generative braking s ystem, t-lle comhn'iation of a supply line, a load driv n dynamo-electric machine having "a field Winding, a .iine switch for connecting said machine to said supply line for regenerative braking operation, an cxciter for exciting said field winding, and means jointly responsive to the voltage of said supply line and the voltage of said dynamo-electric machine for automatically regulating said exciter to maintain the regenerated voltage or" the machine substantially equal to the voltage of the supply line after closure of said line switch.

8. In a regenerative braking system, the combination of a supply line, a regenerative braking dynamo-electric machine having a field winding, a line switch for connecting said machine to said supply line for regenerating braking operation, an cxciter for exciting said field winding, means for separately exciting said exciter, a shunt-wound motor having its armature connected in the excitation circuit of said exciter, and a voltage balancing relay for effecting the closure of said line switclrwhen the regenerated voltage of said machine is in predetermined relation with the voltage of said supply line and for automatically controlling a short circuit around the shunt held winding of said motor thereafter.

9. In a regenerative braking system, the combination of a supply line, a regenerative braking dynamo-electric machine having a field winding, 8. line switch for connecting said machine to said supply line for regenerative braking operation, an exciter for exciting said field winding means jointly responsive to the voltage of said supply line and the regenerated voltage of said dynamo-electric machine for effecting the closure of said line switch when the regenerated voltage is in a predetermined relation with the line voltage and for automatically regulating said exciter to maintain the said voltage relation after closure of said line switch, and independent electro-responsim means controlled jointly in accordance with the exciter voltage and the regenerated currcntof said machine for automatically regulating said exciter independently of said voltage responsive means.

10. In a regenerative braking system, the combination of a supply line, a regenerative braking dynamo-electric machine having a field winding, :1 line switch for connecting said machine to said supply line for regenerative braking operation, an exciter for exciting said field winding, means for separately exciting said exciter, a voltage balancing relay for effecting closure of said linc switch when the regenerated voltage of said machine is in a predetermined relation with the voltage of said supply line and for auto matically controlling the separate excitation of said exciter thereafter, a resistor for limiting the regenerated current of said machine, means for short circuiting said resistor and rendering said voltage balancing relay incfl'ectivc to control the excitation of the said excitrr, and an automatic regulator responsive to the regenerated current of said machine for automatically regulating the excitation of the said exciter after the short circuiting of said resistor.

11. In a regenei" ire braking system, the combination of a. supply line, a regenerative braking dynamo-electric machine having a field winding, an exciter for said field winding, means for regulating said exciter comprising a voltage balancing relay jointly re sponsive to the voltage of said supply line and the regenerated voltage of said dynamoelcctric machine, and an automatic regulator jointly responsive to the voltage of said exciter and the regenerated braking current of the machine, and connections through which the said voltage balancing relay and the said automatic regulator are separately rendered effective to control said exciter during difi'erent phases of regenerative braking operation.

12. In a regenerative braking system the combination of a supply line, a regenerative raking dynamoelectric machine having a field winding, :1 line switch for connecting said machine to said supply line for regenerative braking operation, an exciter for exciting said field winding, a resistor for limiting the regenerated current of the machine upon closure of the line switch, an exciter for exciting said field winding, means for separately exciting said exciter, a shuntwound motor having its armature connected in the excitation circuit of said exciter, a voltage balancing relay for effecting the closure of said line switch when the regenerated voltage of said machine is in a predetermined relation with the voltage of said supply line and for automatically controlling a short circuit around the shunt field winding of said motor with said current limiting resistor in the braking circuit, means for short-circuiling said resistor and rendering said voltage bahincing relay inetl'ccth-e, an automatic regulator lniving a vibratory contact for controlling the short circuit around the shunt field winding of said motor, said regulator having an operating winding for said contact connected to be energized responsivcly to the voltage of said cxcitcr, and a differential operating winding for said contact connected to be energized in accordance with the regenerated current of said dynamo-electric machine, and means for \'ar ,'ng the excitation of said first regulator contactoperating winding independently of the voltage of said exciter to control the regenerative braking current of said machine.

In witness whereof, we have hereunto set our hands respectively the th day of May, 1927, and the 21st day of May, 1927.

RUDOLPH D. KRAPE. WILLIAM S, H. HAMILTON.

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